gdb/mi: add a '--force-condition' flag to the '-break-insert' cmd

Add a '--force-condition' flag to the '-break-insert' command to be
able to force conditions.  Because the '-dprintf-insert' command uses
the same mechanism as the '-break-insert' command, it obtains the
'--force-condition' flag, too.

gdb/ChangeLog:
2021-05-06  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* mi/mi-cmd-break.c (mi_cmd_break_insert_1): Recognize the
	'--force-condition' flag to force the condition in the
	'-break-insert' and '-dprintf-insert' commands.
	* NEWS: Mention the change.

gdb/testsuite/ChangeLog:
2021-05-06  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* gdb.mi/mi-break.exp (test_forced_conditions): New proc that
	is called by the test.

gdb/doc/ChangeLog:
2021-05-06  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	* gdb.texinfo (GDB/MI Breakpoint Commands): Mention the
	'--force-condition' flag of the '-break-insert' and
	'-dprintf-insert' commands.